Stephen Anderson, June 29, 2009

NOAA Teacher at Sea
Stephen Anderson
Onboard NOAA Ship Miller Freeman
June 28 July 12, 2009

The CTD Instruments
The CTD Instruments

Mission: Hake Survey
Geographic Region: California
Date: June 29, 2009

We anchored in Monterey Bay.  After putting the anchor down there were several tests that had to be made.  The first was to send in SCUBA divers to check our propeller.  The second test was to check on the transducers for our sonar.  The third was to put over the side the CTD (conductivity, temperature, and density instruments).  This instrument is useful not only to tell the composition of the water, but also to determine currents. Included in this set of instruments is an automatic camera that will catch video of the small animals (micro-organisms) at various depths (what the fish eat).  The fourth test was to send three balls of different sizes and materials to hang under the boat using what we in Michigan would call salmon downriggers.  Dr. Chu, our chief scientist, and Stan Tomich, our engineer, can control these miniature cranes to raise and lower these balls.  They can then calibrate (set the readings on the sonar sensors) to make sure they have the correct depth for the fish they will be able to see with the sonar.  The sonar array in this boat is accurate to within one centimeter. Later tonight we will weigh anchor to go further south to begin our chase after hake.

Divers over the side to check the propeller and sonar.
Divers over the side to check the propeller and sonar.

For those of you who don’t know hake.  This is a cod type of fish that is very important to the fish industry on the west coast of the US and Canada.  If you’ve had a fish stick, you’ve probably had hake.

We were visited today by some very interesting animals: several species of jelly fish, several sea lions, a few dolphins, and a mola mola fish which is sometimes called a sun fish.

A Mola Mola, or Sun Fish. This guy was probably 6 feet in length.
A Mola Mola, or Sun Fish. This guy was probably 6 feet in length.